1. Field of the Invention
The invention relates to an alpine ski binding element, intended to retain the boot in support on a ski, and to release it in case of excessive bias.
2. Discussion of Background and Material Information
Retaining a boot in support on a ski by means of a front binding element and a rear binding element is known. The primary function of these elements is to retain the boot on the ski in such a way as to enable the skier to guide his or her ski in particular by the efforts that the skier transmits to the boot as a function of the path that the skier wishes to follow and the reactions that the ski transmits to the skier. Another function of the binding elements is to relax this boot retention, i.e., to release the boot when the efforts between the boot and the ski become extreme to the point of causing injuries to the leg of the skier. It is difficult to discern at which point a bias becomes dangerous to the leg of the skier. Releasing the boot unnecessarily constitutes what has been designated an ill-timed release.
Each retention element usually has a jaw borne by a body, that is mobile against the return force exerted by an energy spring, generally a compression spring.
The present invention more particularly relates to a front binding element. Usually, the front binding element reacts to a lateral bias of the front end of the boot. Such a bias results from a pure torsional bias on the leg of the skier.
Certain binding elements also react to a vertical upward bias. One such bias corresponds to a rearward fall of the skier. European Patent Publication No. 102 868, for example, describes such a binding.
Other bindings have a compensation mechanism that reacts in the case of torsional bias combined with a forward fall of the skier. Such a mechanism is described for example in German Patent Publication No. 29 05 837. This mechanism comprises a boot support plate that is vertically mobile, whose movement caused by vertical downward pressure of the boot reduces the return force that the spring exerts on the law.
Another mechanism is described in German Patent Publication No. 33 35 878. This mechanism also comprises a boot support plate that is vertically mobile and that forces the jaw to be displaced in the direction of the boot release. Such devices compensate the increase in friction of the boot on its supports, that the forward component of the fall induces. Such mechanisms are satisfactory as long as the lateral component of the fall remains dominant with respect to the vertical component.
But, it happens that in the case of certain falls called "pre-torsion" i.e. with a forward component and a lateral component, the lateral component is not sufficient to cause the lateral rocking or pivoting of the jaw. One then experiences a twisting of the boot which becomes wedged between the jaw and its support plate. Currently known compensation mechanisms are not sufficiently active to cause the opening of the jaw. Sometimes falls are dangerous and cause injuries in particular in the area of the knees of the skier.
On this subject it has also been noted that the knee of the skier is more or less fragile according to the twisting or torque direction in which the leg is biased. Thus, it appeared important to seek improvement of the protection of the knee in particular in the torque direction where it is the most fragile.